Lenomiya Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Lenomiya Observatory clear sky chart from 2005-11-05 to 2017-09-23.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
78%
15675
38%
46982
34%
15637
82%
15637
57%
21724

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
77%
718
34%
2327
37%
716
81%
716
52%
1076
January16th to endNight
71%
768
38%
2496
38%
768
77%
768
47%
1201
February1st to 15thNight
74%
700
38%
2174
38%
700
80%
700
55%
1003
February16th to endNight
68%
632
37%
1874
36%
632
73%
632
49%
942
March1st to 15thNight
72%
720
41%
1980
33%
720
79%
720
61%
954
March16th to endNight
78%
768
41%
2112
31%
768
85%
768
66%
971
April1st to 15thNight
69%
710
35%
1969
23%
710
77%
710
60%
943
April16th to endNight
72%
540
47%
1716
38%
540
83%
540
75%
637
May1st to 15thNight
74%
539
41%
1619
31%
539
82%
539
73%
653
May16th to endNight
77%
561
41%
1684
32%
561
82%
561
74%
671
June1st to 15thNight
85%
540
36%
1620
31%
540
86%
540
74%
651
June16th to endNight
89%
540
35%
1620
30%
540
90%
540
73%
659
July1st to 15thNight
83%
510
25%
1530
21%
510
83%
510
48%
781
July16th to endNight
82%
564
27%
1593
22%
531
82%
531
41%
880
August1st to 15thNight
84%
539
29%
1611
26%
536
84%
536
46%
830
August16th to endNight
83%
646
34%
1882
31%
646
83%
646
46%
996
September1st to 15thNight
81%
720
32%
1980
28%
720
83%
720
50%
1062
September16th to endNight
85%
688
46%
1903
38%
688
89%
688
71%
843
October1st to 15thNight
83%
660
42%
1892
36%
660
86%
660
67%
836
October16th to endNight
86%
704
45%
2112
40%
704
90%
704
70%
873
November1st to 15thNight
85%
700
43%
2112
41%
700
87%
700
67%
893
November16th to endNight
79%
720
40%
2340
40%
720
84%
720
56%
1025
December1st to 15thNight
76%
720
39%
2340
41%
720
79%
720
51%
1097
December16th to endNight
72%
768
37%
2496
39%
768
76%
768
44%
1247

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
3212213345%69%
47918
Night
3112212346%69%
47179
TransparencyDay
16%2311%24%41%
47613
Night
16%2411%23%41%
46985
SeeingDay
3314%28%34%15%
5487
Night
3110%41%37%4
15684

By Month

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
5%313213235%66%
1611
16th to endDay
6%213213335%64%
1728
February1st to 15thDay
2313312335%68%
1685
16th to endDay
5%313223336%63%
1598
March1st to 15thDay
421221234470%
1980
16th to endDay
2213212335%71%
2112
April1st to 15thDay
222212246%73%
1976
16th to endDay
211112383%
2241
May1st to 15thDay
111223480%
2331
16th to endDay
1111112383%
2429
June1st to 15thDay
1111212382%
2340
16th to endDay
11121122381%
2340
July1st to 15thDay
2313325%6%6%9%55%
2340
16th to endDay
3425%437%6%7%12%42%
2467
August1st to 15thDay
3223435%46%8%55%
2340
16th to endDay
3224245%6%8%59%
2315
September1st to 15thDay
4213324447%60%
1980
16th to endDay
21221122379%
1893
October1st to 15thDay
112212335%76%
1738
16th to endDay
1121123479%
1760
November1st to 15thDay
12112236%77%
1746
16th to endDay
421321212474%
1620
December1st to 15thDay
6%312312346%64%
1620
16th to endDay
6%213313347%61%
1728
January1st to 15thNight
5%112312345%66%
2327
16th to endNight
7%313223335%64%
2496
February1st to 15thNight
3312212237%68%
2164
16th to endNight
4213424446%61%
1874
March1st to 15thNight
4211212235%71%
1980
16th to endNight
211212236%74%
2112
April1st to 15thNight
311221323471%
1969
16th to endNight
1111111385%
1716
May1st to 15thNight
1111237%77%
1619
16th to endNight
1111111285%
1684
June1st to 15thNight
11111225%81%
1620
16th to endNight
111122481%
1620
July1st to 15thNight
22133245%7%12%54%
1620
16th to endNight
32135%35%7%8%15%42%
1701
August1st to 15thNight
11145%25%5%6%9%54%
1620
16th to endNight
12135%35%5%5%8%56%
1882
September1st to 15thNight
211343445%8%58%
1980
16th to endNight
11111233478%
1903
October1st to 15thNight
212212235%75%
1892
16th to endNight
111111122480%
2112
November1st to 15thNight
2111211225%77%
2112
16th to endNight
321232222472%
2340
December1st to 15thNight
6%212212345%66%
2340
16th to endNight
6%313322346%61%
2496

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
21%2315%28%28%
1612
16th to endDay
21%2315%28%29%
1728
February1st to 15thDay
20%1314%28%31%
1685
16th to endDay
22%1213%32%27%
1598
March1st to 15thDay
17%117%30%42%
1980
16th to endDay
16%128%30%41%
2112
April1st to 15thDay
13%116%34%43%
1976
16th to endDay
8%15%22%60%
2241
May1st to 15thDay
9%116%21%59%
2331
16th to endDay
9%1420%62%
2432
June1st to 15thDay
9%214%72%
2340
16th to endDay
9%11310%72%
2340
July1st to 15thDay
23%48%14%18%30%
2201
16th to endDay
30%7%13%22%18%7%
2312
August1st to 15thDay
25%48%16%17%26%
2325
16th to endDay
21%47%19%22%24%
2315
September1st to 15thDay
22%46%13%23%29%
1980
16th to endDay
12%11426%53%
1893
October1st to 15thDay
12%238%25%47%
1738
16th to endDay
10%128%25%51%
1760
November1st to 15thDay
10%1110%33%42%
1746
16th to endDay
16%218%28%42%
1620
December1st to 15thDay
21%2317%30%24%
1620
16th to endDay
22%25%21%32%15%
1728
January1st to 15thNight
19%25%12%27%32%
2327
16th to endNight
23%1313%27%30%
2496
February1st to 15thNight
18%1414%24%36%
2175
16th to endNight
22%2313%27%30%
1874
March1st to 15thNight
16%118%24%47%
1980
16th to endNight
13%128%29%44%
2112
April1st to 15thNight
16%125%30%43%
1969
16th to endNight
7%16%20%64%
1716
May1st to 15thNight
8%126%22%58%
1620
16th to endNight
8%115%17%65%
1685
June1st to 15thNight
9%313%71%
1620
16th to endNight
9%1247%75%
1620
July1st to 15thNight
20%5%8%18%15%30%
1530
16th to endNight
25%7%14%22%20%10%
1593
August1st to 15thNight
22%5%11%18%15%27%
1611
16th to endNight
22%5%8%16%23%23%
1882
September1st to 15thNight
22%46%18%21%26%
1980
16th to endNight
10%116%25%54%
1903
October1st to 15thNight
12%2211%21%49%
1892
16th to endNight
10%128%19%57%
2112
November1st to 15thNight
12%129%27%47%
2112
16th to endNight
16%229%24%45%
2340
December1st to 15thNight
20%1314%28%31%
2340
16th to endNight
25%2417%29%21%
2496

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
15%28%45%24%3
90
16th to endDay
7%38%36%25%19%
96
February1st to 15thDay
45%14%31%41%4
200
16th to endDay
5%7%22%35%23%5%
238
March1st to 15thDay
48%21%30%22%12%
270
16th to endDay
111%20%28%26%11%
288
April1st to 15thDay
5%7%26%26%21%12%
269
16th to endDay
111%27%32%20%5%
270
May1st to 15thDay
19%25%30%24%8%
288
16th to endDay
1321%30%33%9%
330
June1st to 15thDay
2217%38%28%10%
315
16th to endDay
26%34%36%19%
315
July1st to 15thDay
16%28%41%20%
305
16th to endDay
3218%45%28%
327
August1st to 15thDay
3319%45%28%
315
16th to endDay
315%47%33%
332
September1st to 15thDay
7%6%29%39%14%
315
16th to endDay
4116%29%35%12%
284
October1st to 15thDay
2215%29%32%16%
178
16th to endDay
41115%54%23%
96
November1st to 15thDay
3114%20%45%15%
90
16th to endDay
3410%40%37%4
90
December1st to 15thDay
47%24%47%15%
90
16th to endDay
12%318%32%29%4
96
January1st to 15thNight
5%9%51%28%3
720
16th to endNight
9%112%44%30%2
768
February1st to 15thNight
4213%47%28%3
704
16th to endNight
5%218%50%21%2
632
March1st to 15thNight
4217%42%29%3
720
16th to endNight
2213%44%32%4
768
April1st to 15thNight
3219%47%25%1
710
16th to endNight
2320%45%25%2
540
May1st to 15thNight
1218%45%29%1
540
16th to endNight
2116%41%35%1
563
June1st to 15thNight
119%53%33%1
540
16th to endNight
5%41%50%1
540
July1st to 15thNight
3431%53%6%
510
16th to endNight
3318%63%11%
564
August1st to 15thNight
2124%60%10%
539
16th to endNight
1323%60%10%
646
September1st to 15thNight
26%28%55%6%
720
16th to endNight
27%39%44%5%
688
October1st to 15thNight
29%44%38%3
660
16th to endNight
26%40%41%8%
704
November1st to 15thNight
27%45%39%3
700
16th to endNight
310%44%36%3
720
December1st to 15thNight
7%18%45%34%2
720
16th to endNight
8%29%49%25%3
768
Page generated at 2017-09-24 06:15:47. Version ac04

Copyright 2017 A. Danko


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